xfrm: Fix eth_hdr(skb)->h_proto to reflect inner IP version

IPSec tunnel mode supports encapsulation of IPv4 over IPv6 and vice-versa. The outer IP header is stripped and the inner IP inherits the original Ethernet header. Tcpdump fails to properly decode the inner packet in case that h_proto is different than the inner IP version. Fix h_proto to reflect the inner IP version. Signed-off-by: Yossi Kuperman <yossiku@mellanox.com> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
mariux64 · Jan 23, 2018 · 5efec5c · 5efec5c
1 parent aa5dd6f
commit 5efec5c
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diff --git a/net/ipv4/xfrm4_mode_tunnel.c b/net/ipv4/xfrm4_mode_tunnel.c
@@ -92,6 +92,7 @@ static int xfrm4_mode_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
 
 	skb_reset_network_header(skb);
 	skb_mac_header_rebuild(skb);
+	eth_hdr(skb)->h_proto = skb->protocol;
 
 	err = 0;
 

diff --git a/net/ipv6/xfrm6_mode_tunnel.c b/net/ipv6/xfrm6_mode_tunnel.c
@@ -92,6 +92,7 @@ static int xfrm6_mode_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
 
 	skb_reset_network_header(skb);
 	skb_mac_header_rebuild(skb);
+	eth_hdr(skb)->h_proto = skb->protocol;
 
 	err = 0;